CCTV CCTV System Components 5 — Questions and Answers
Question 1: What is the purpose of a 'sync generator' in a legacy analog CCTV system?
- Generate encrypted sync codes to prevent unauthorized viewing
- Provide a common timing reference signal so multiple cameras stay synchronized for multiplexed recording (Correct answer)
- Synchronize the timestamps of digital IP cameras across a network
- Generate test patterns to verify monitor calibration
Correct answer: Provide a common timing reference signal so multiple cameras stay synchronized for multiplexed recording
A sync generator produces a master reference signal that locks multiple analog cameras to the same timing, preventing frame tearing or rolling when cameras are switched or multiplexed.
Question 2: A technician needs to run CCTV cable through a high-EMI industrial environment. Which cable type is most appropriate?
- RG-59 coaxial cable
- Cat5e UTP cable
- RG-6 coaxial cable with foil and braid shielding
- Single-mode fiber optic cable (Correct answer)
Correct answer: Single-mode fiber optic cable
Single-mode fiber optic cable transmits light signals, making it completely immune to electromagnetic interference — the best choice for high-EMI environments like factories with large motors.
Question 3: What does the term 'back focus adjustment' refer to in a CCTV camera?
- Adjusting the camera's iris to compensate for backlit scenes
- Setting the correct distance between the lens and the image sensor to achieve sharp focus (Correct answer)
- Programming the NVR to retrieve footage from a set time in the past
- Configuring the camera to reverse the image orientation
Correct answer: Setting the correct distance between the lens and the image sensor to achieve sharp focus
Back focus adjustment positions the image sensor (or CCD/CMOS chip) at the correct focal distance from the lens so the image remains sharp across the full zoom range.
Question 4: In a CCTV installation, what is the purpose of a 'termination resistor' (75-ohm) at the end of a coaxial video run?
- Provide power to the camera at the end of a long cable run
- Prevent signal reflections by matching the cable's characteristic impedance (Correct answer)
- Step down the voltage from 12V DC to 5V DC
- Block DC voltage from reaching the recording equipment
Correct answer: Prevent signal reflections by matching the cable's characteristic impedance
A 75-ohm termination resistor at the end of a coaxial cable absorbs the signal and prevents it from reflecting back, which would cause ghost images or signal distortion.
Question 5: What is the function of an OSD (On-Screen Display) menu in a CCTV camera?
- Overlay the surveillance footage onto a digital map
- Allow configuration of camera settings such as exposure, white balance, and motion detection via an on-screen interface (Correct answer)
- Display real-time analytics data like people count to end users
- Stream live video to a remote monitoring station
Correct answer: Allow configuration of camera settings such as exposure, white balance, and motion detection via an on-screen interface
The OSD menu is accessed through the camera's joystick or software interface and lets technicians configure internal camera parameters without needing a separate software application.
Question 6: Which CCTV camera technology uses a coaxial cable to transmit HD video without converting to IP, maintaining analog infrastructure?
- ONVIF Profile S
- HD-TVI, HD-CVI, or AHD (analog HD over coax) (Correct answer)
- SFP fiber transceiver
- RTSP streaming protocol
Correct answer: HD-TVI, HD-CVI, or AHD (analog HD over coax)
HD-TVI, HD-CVI, and AHD are analog HD-over-coax technologies that transmit 1080p or higher resolution video over existing RG-59/RG-6 coaxial cable without requiring IP network infrastructure.
Question 7: What is the primary purpose of a CCTV 'video wall controller' in a large security control room?
- Record video from all cameras to a redundant backup drive
- Manage and distribute multiple video sources across an array of monitors in flexible display layouts (Correct answer)
- Convert all camera feeds to a single composite video output
- Authenticate operators before granting access to camera controls
Correct answer: Manage and distribute multiple video sources across an array of monitors in flexible display layouts
A video wall controller receives multiple video inputs and outputs them across an array of monitors, allowing operators to create custom layouts, zoom in on specific feeds, and manage large-scale surveillance displays.
CCTV CCTV System Components 5
What is the purpose of a 'sync generator' in a legacy analog CCTV system?